content: /*
   * Copyright 2011-2016 David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package ix;
  
  import java.util.*;
  
  /**
   * Buffer while the predicate returns true.
   *
   * @param <T> the value type
   */
  final class IxBufferWhile<T> extends IxSource<T, List<T>> {
  
      final IxPredicate<? super T> predicate;
  
      IxBufferWhile(Iterable<T> source, IxPredicate<? super T> predicate) {
          super(source);
          this.predicate = predicate;
      }
  
      @Override
      public Iterator<List<T>> iterator() {
          return new BufferSplitIterator<T>(source.iterator(), predicate);
      }
  
      static final class BufferSplitIterator<T> implements Iterator<List<T>> {
  
          final Iterator<T> source;
  
          final IxPredicate<? super T> predicate;
  
          boolean done;
  
          List<T> buffer;
  
          List<T> next;
  
          BufferSplitIterator(Iterator<T> source, IxPredicate<? super T> predicate) {
              this.source = source;
              this.predicate = predicate;
          }
  
          @Override
          public boolean hasNext() {
              List<T> b = buffer;
              if (b == null) {
                  if (done) {
                      return false;
                  }
  
                  b = next;
                  if (b == null) {
                      b = new ArrayList<T>();
                  }
  
                  Iterator<T> src = source;
                  while (src.hasNext()) {
                      T v = src.next();
  
                      if (!predicate.test(v)) {
                          buffer = b;
                          b = new ArrayList<T>();
                          b.add(v);
                          next = b;
                          return true;
                      }
  
                      b.add(v);
                  }
  
                  if (b.isEmpty()) {
                      done = true;
                      return false;
                  }
  
                  buffer = b;
                  done = true;
              }
              return true;
          }
  
          @Override
          public List<T> next() {
              if (hasNext()) {
                  List<T> b = buffer;
                  buffer = null;
                  return b;
              }
              throw new NoSuchElementException();
          }
  
          @Override
          public void remove() {
              throw new UnsupportedOperationException();
          }
      }
  }
  